.mian, .mian .vm {
  min-height: 100%;
  padding-bottom: 3rem;
}
nav {
  position: fixed;
  bottom:0px;
  width: 100%;
  border-top: 1px solid skyblue;
  .item {
    display: block;
    height: 3rem;
    line-height: 3rem;
    text-align: center;
  }
  .item, .item * {
    color: black;
  }
  .item.active *{
    color: skyblue
  }
}
header {
  position: relative;
  h3 {
    height: 2rem;
    margin-top: 0px;
    line-height: 2rem;
    background: skyblue;
  }
  .back {
    position: absolute;
    top:0px;
    left: 0px;
    height: 2rem;
    width: 2rem;
    font-size: 1.5rem;
    line-height: 2rem;
    color: white;
  }
}
form {
  padding: 0rem 0.4rem;
}
  